(i) Field of the Invention
This invention relates to transgenic rice plants, plant material and seeds, characterized by harboring a specific transformation event, particularly by the presence of a gene encoding a protein that confers herbicide tolerance, at a specific location in the rice genome. The rice plants of the invention combine the herbicide tolerant phenotype with an agronomic performance, genetic stability and adaptability to different genetic backgrounds equivalent to the non-transformed rice line in the absence of weed pressure. This invention further provides methods and kits for identifying the presence of plant material comprising specifically transformation event GAT-OS3 in biological samples.
(ii) Description of the Related Art
The phenotypic expression of a transgene in a plant is determined both by the structure of the gene itself and by its location in the plant genome. At the same time the presence of the transgene (in a foreign DNA) at different locations in the genome will influence the overall phenotype of the plant in different ways. The agronomically or industrially successful introduction of a commercially interesting trait in a plant by genetic manipulation can be a lengthy procedure dependent on different factors. The actual transformation and regeneration of genetically transformed plants are only the first in a series of selection steps, which include extensive genetic characterization, breeding, and evaluation in field trials, eventually leading to the selection of an elite event.
Rice production is commonly threatened by various weeds. Some of these can be highly competitive and in cases of severe infestation can result in yield loss of such magnitude that it makes the crop economically unattractive. For direct-seeded, mechanized rice cultivation typical of temperate production, both cultural practices (e.g. crop rotation, irrigation management) and herbicides are necessary to control weeds (Hill et al. 1994, Aust. J. Exp. Agric. 34:1021-1029).
The unequivocal identification of an elite event is becoming increasingly important in view of discussions on Novel Food/Feed, segregation of GMO and non-GMO products and the identification of proprietary material. Ideally, such an identification method is both quick and simple, without the need for an extensive laboratory set-up. Furthermore, the method should provide results that allow unequivocal determination of the elite event without expert interpretation, but which hold up under expert scrutiny if necessary. Specific tools for use in the identification of elite event GAT-OS3 in biological samples are described herein.
U.S. Pat. Nos. 6,333,449, 6,468,747 and 6,933,111 describe transgenic rice plants comprising a glufosinate tolerance gene. Such transgenic rice plants are tolerant to the herbicidal compounds phosphinothricin (PPT, also called glufosinate) or bialaphos (see also for example U.S. Pat. Nos. 5,646,024, 5,648,477 and 5,561,236) and salts and optical isomers thereof.
The transgenic rice plants contain a chimeric gene conferring tolerance to glufosinate, comprising the bar gene (Thompson et al, 1987, EMBO J. 6:2519-2523; Deblock et al. 1987, EMBO J. 6:2513-2518) encoding the enzyme phosphinothricin acetyl transferase (PAT), under control of the 35S promoter from Cauliflower Mosaic Virus (Odell et al., 1985, Nature 313:810-812).
The transformation of monocotyledonous plants is described in U.S. Pat. Nos. 5,641,664, 5,712,135, 6,002,070 and 6,074,877. Transformation of rice with the bar gene by electroporation of aggregated suspension cells is described in U.S. Pat. No. 5,679,558.
However, none of the prior art disclosures teach or suggest the present invention.